Self-contained EEG recording system

ABSTRACT

Disclosed systems include a self-contained electroencephalogram (EEG) recording patch comprising a first electrode, a second electrode and wherein the first and second electrodes cooperate to measure a skin-electrode impedance, a substrate containing circuitry for generating an EEG signal from the measured skin-electrode impedance, amplifying the EEG signal, digitizing the EEG signal, and retrievably storing the EGG signal. The patch also comprises a power source and an enclosure that houses the substrate, the power source, and the first and second electrodes in a unitary package.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application, under 35 U.S.C. § 119, claims the benefit of U.S.Provisional Patent Application Ser. No. 62/289,837 filed on Feb. 1,2016, and entitled “Self-contained EEG Recording System,” the contentsof which are hereby incorporated by reference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates to a self-contained electroencephalogram(EEG) recording device. In particular, some disclosed embodiments allowfor monitoring EEG seizure activity from the scalp. Further disclosedembodiments may also allow recording epochs of EEG from the scalp.

BACKGROUND

The disclosures of each and every reference noted within this disclosureare hereby fully incorporated herein by reference.

There is a present need for an EEG recording system that isself-contained as one unit, is as small as possible, is simple byreducing the complexity of analyzing data on the device, and relativelywater tight. In such cases where the desired EEG recording is forseizures, or determining sleep quality, it is not necessary to analyzethe recorded data in real time, thus simplifying the need for increasedprocessing power on the device. Many existing EEG recording systems,such as U.S. Pat. No. 8,688,209 and U.S. Pat. App. Pub. No.2008/0091090, are concerned with analyzing the data for spikes orseizures in real time and displaying that data, or some indication ofthat data, on a display attached to the device.

The majority of sleep staging devices are incorporated as part of maskssuch as those in U.S. Pat. Nos. 7,848,794 and 8,204,584, or withoutmasks that are attached to the scalp with a harness, such as those inU.S. Pat. App. Pub. No. 2011/0098593, or a head band and removable dataacquisition box such as those in WO/2010/107928, and operate withmultiple modes, such as those in U.S. Pat. No. 8,870,764. These devicesare typically used in whole, or in part, to help diagnose obstructivesleep apnea (OSA), and tend to have multiple connections such as thosein U.S. Pat. App. Pub. No. 2008/0319277. They can also be configured toprovide feedback to the user as a means to optimize sleep such as thosein U.S. Pat. No. 8,628,462.

Other physiological monitoring devices require multiple hinged “wings”containing electrodes separate from a central body, such as those inU.S. Pat. No. 8,538,503, or are designed to be reusable/recoverable suchas those in U.S. Pat. App. Pub. No. 2014/0206977. The above-describedlimitations and drawbacks of existing systems may be disadvantageous orundesirable as would be appreciated by those of skill in the art. Otherdrawbacks and disadvantages of existing systems also exist.

SUMMARY

Accordingly, the disclosed systems and methods address the drawbacks anddisadvantages of existing systems.

Accordingly disclosed systems include a self-containedelectroencephalogram (EEG) recording patch comprising a first electrode,a second electrode and wherein the first and second electrodes cooperateto measure a skin-electrode impedance, a substrate containing circuitryfor sensing an EEG signal from the skin-electrode impedance, amplifyingthe EEG signal, digitizing the EEG signal, and retrievably storing theEEG signal. The patch also comprises a power source and an enclosurethat houses the substrate, the power source, and the first and secondelectrodes in a unitary package.

Further disclosed embodiments may comprise an indicator that indicatesan active and an inactive state of the patch. In some embodiments, theindicator further comprises an LED. In still further embodiments, theindicator further comprises an audible tone generator.

In some embodiments, the substrate containing circuitry furthercomprises circuitry for electromechanical activation of the patch. Insome embodiments, the circuitry for electromechanical activation of thepatch further comprises at least one switch. In some embodiments, thecircuitry for electromechanical activation of the patch furthercomprises at least one Hall-effect sensor.

In some embodiments, the self-contained EEG recording patch may comprisea third electrode. In some embodiments, the enclosure comprises asubstantially waterproof polymer. In some embodiments, the firstelectrode and the second electrode further comprise memory shape alloyelectrodes, and plungers to inject the memory shape alloy electrodesinto a scalp and mechanically fix the patch thereto.

Further disclosed embodiments include a seizure alerting systemcomprising a self-contained EEG recording patch comprising a firstelectrode, a second electrode, wherein the first and second electrodescooperate to measure a skin-electrode impedance, a substrate containingcircuitry for sensing an EEG signal from the skin-electrode impedance,amplifying the EEG signal, digitizing the EEG signal, and retrievablystoring the EEG signal. The EEG patch also comprises a power source, atransmitter for transmitting the EEG signal, and an enclosure thathouses the substrate, the power source, the transmitter, and the firstand second electrodes in a unitary package. The alerting system furthercomprises a base station that receives the transmitted EEG signal,monitors the EEG signal for an indication of a seizure, and signals analert when a seizure is indicated.

In some embodiments, the seizure alerting system further comprises aremote alerting device capable of communicating with the base stationthat signals an alert when the base station signals an alert. In someembodiments, remote alerting device comprises a smartphone.

Other embodiments of the patch may include fabrication of electrodes onprinted circuit boards separate from the circuit board or substrate.These electrode printed circuit boards are then attached to the maincircuit board or substrate using standard surface mount reflowelectronics assembly techniques. This provides an advantage byeliminating the requirement for exotic and expensive metal surfacefinishes (that are typically required on most electrodes) whenfabricating the circuit board or substrate. These electrode printedcircuit boards are referred to herein as a “dais boards” and the methodof fabrication is referred to herein as “dais assembly.” The surfacefinish of the electrode on printed circuit boards may be selective gold,immersion silver, carbon, or other materials suitable as a biopotentialelectrode interface. Other embodiments are also possible.

Other disclosed embodiments include a biopotential recording systemcomprising a first dais board comprising a first electrode, a seconddais board comprising a second electrode, and wherein the first andsecond electrodes sense a voltage, a substrate containing circuitry forgenerating an EEG signal from the voltage, amplifying the EEG signal,digitizing the EEG signal, and retrievably storing the EGG signal. Thebiopotential recording system also comprises a power source and anenclosure that houses the substrate, the power source, and the daisboard in a unitary package.

In some embodiments, the biopotential recording system further comprisesan indicator that indicates an active and an inactive state of thesystem. In some embodiments, the indicator further comprises an LED oran audible tone generator.

In some embodiments, the substrate containing circuitry furthercomprises circuitry for electromechanical activation of the system. Insome embodiments, the circuitry for electromechanical activation of thesystem further comprises at least one switch or at least one Hall-effectsensor. Other embodiments are also possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective top view and bottom view illustration of anembodiment of a self-contained EEG recording patch as a seizure countingtool in accordance with the disclosure.

FIG. 2 is a perspective top view of an illustration of an embodiment ofa self-contained EEG recording patch for recording frontal EEG below thehairline in accordance with the disclosure.

FIG. 3 is a schematic illustration of components within a self-containedEEG recording patch in accordance with the disclosure.

FIG. 4 is a perspective bottom view illustration of replaceableconductive hydrogels that interface between the self-contained EEGrecording patch and the scalp on an embodiment of a three-electrode EEGdevice in accordance with the disclosure.

FIG. 5 is a perspective bottom view of an illustration of replaceableconductive hydrogels that interface between the self-contained EEGrecording patch and the scalp on an embodiment of a two-electrode devicein accordance with the disclosure.

FIG. 6 is an exemplary state diagram for an embodiment of theself-contained EEG recording patch in accordance with the disclosure.

FIG. 7 is an exemplary state diagram for another embodiment of theself-contained EEG recording patch in accordance with the disclosure.

FIG. 8 is an electronic circuit layout illustration for an embodiment ofthe self-contained EEG recording patch in accordance with the disclosureshowing components and power source with the patch enclosure removed.

FIG. 9 is an electronic circuit layout illustration for an embodiment ofthe self-contained EEG recording patch in accordance with the disclosureshowing components without the power source and without the patchenclosure.

FIG. 10 is an electronic circuit layout illustration for the top andbottom sides of an embodiment of the self-contained EEG recording patchshowing components in another layout in accordance with the disclosure.

FIG. 11 is an exploded perspective view of an electronic circuit layoutillustration for an embodiment of the self-contained EEG recording patchin accordance with the disclosure showing the enclosure overmolding,power source, transmitter and circuit backbone.

FIG. 12 is a schematic illustration of an embodiment of theself-contained EEG recording device as a seizure alerting method inaccordance with the disclosure whereby the transmitter attached to thescalp transmits EEG in real-time to a base station that analyzes the EEGfor seizures and stores the EEG for later retrieval.

FIG. 13 is a schematic illustration demonstrating the concept ofsingle-channel seizure detection based on scalp location in accordancewith the disclosure.

FIG. 14 is a schematic illustration of a map of the scalp showing anexample of single channel seizure detection performance as a probabilitymap for an individual person based on standard EEG electrode locationsin accordance with the disclosure.

FIG. 15 is an exploded perspective view of the electronic circuit layoutillustration for the bottom of an embodiment of the self-contained EEGrecording patch in accordance with the disclosure showing components,data I/O, dais boards off of the substrate, and power source with thepatch enclosure removed.

FIG. 16 is an electronic circuit layout illustration for the bottom ofan embodiment of the self-contained EEG recording patch in accordancewith the disclosure showing components, data I/O, dais boardssurface-mounted to the substrate, and power source with the patchenclosure removed.

FIG. 17 is a sectioned view of the electronic circuit layoutillustration for the bottom of an embodiment of the self-contained EEGrecording patch in accordance with the disclosure showing components,memory shape alloy electrodes in their storage state, the plungers usedto inject the memory shape alloy electrodes into the scalp, and powersource with the patch enclosure.

FIG. 18 is a top perspective view of an embodiment of the self-containedEEG recording patch in accordance with the disclosure showing theplungers with the patch enclosure.

FIG. 19 is a side view of an embodiment of the self-contained EEGrecording patch in accordance with the disclosure showing memory shapealloy electrodes in their deployed state but not yet retaining theirmemory shape, and the plungers used to inject the memory shape alloyelectrodes into the scalp with the patch enclosure.

FIG. 20 is a sectioned view of the memory shape alloy mechanism in itsstorage state with plunger.

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and will be described in detail herein. However,it should be understood that the disclosure is not intended to belimited to the particular forms disclosed. Rather, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

FIG. 1 is a perspective top view and bottom view illustration of anembodiment of a self-contained EEG recording patch 1 as a seizurecounting tool in accordance with the disclosure. As shown in the topview (left side of FIG. 1), the patch 1 is self-contained in anenclosure 2. In some embodiments, the enclosure 2 may be formed of aplastic, polymer, composite, or the like that is water-resistant,waterproof, or the like.

For the embodiment of FIG. 1, the enclosure 2 contains all of theelectronics for recording EEG from at least two electrodes 4, 5. Theelectrodes 4, 5, are on the bottom, or scalp facing, side shown on theright side of FIG. 1. Also included on the bottom, or scalp facing, sideare pins, or other interface, for I/O programming and data retrieval 10.

In some embodiments, enclosure 2 may house a circuit board or substrate20, which provides connections for electrodes 4, 5, and optionally 6(for 3-electrode embodiments), amplification circuitry 7, data processor8, storage 9, one or more switches 15 to activate/inactivate therecording state, one or more indicators 12 of the recording state, apower source 11, I/O programming and data retrieval 10. Electrodes 4, 5,6 may be formed of any suitable material. For example, electrodes 4, 5,6 may comprise gold, silver, silver-silver chloride, carbon,combinations of the foregoing, or the like. As noted above, the entirepatch 1 may be self-contained in a watertight enclosure 2. In the someembodiments, the patch 1 is designed to be a self-contained EEG machinethat is one-time limited use per user and disposable.

In the FIG. 1 embodiment, the self-contained patch 1 has two electrodes4, 5 and is used as a discrete, single-channel tool to count seizures.In most instances it is desirable, but not necessary, that the user hashad a previous diagnosis of a seizure disorder using traditional wiredEEG based on the 10-20 montage using the bipolar derivation. Thisdiagnosis provides clinical guidance as to the most optimal location toplace the self-contained patch 1 for recording electrographic seizureactivity in an individual user. The electrode 4, 5 spacing uses abipolar derivation to form a single channel.

The self-contained patch 1 can be placed anywhere on the scalp of apatient to record EEG. Ideally, the patch 1 may be packaged such thatremoval from the package activates the circuitry. This may beaccomplished by the packaging having electromechanical activation, suchas a magnetic component that, when removed, eliminates a magnetic fieldaround the patch. In the absence of the magnetic field, magneticfield-sensitive components 17 within the patch, such as Reed- andHall-effect type elements, may be configured to bring the patch out of asleep-state and into a record-state. In some embodiments, theself-contained patch 1 may also include an indicator 12 of the change inrecording state from record to sleep and from sleep to record. Forexample, the indicator 12 may be an LED element 13 that flashes toindicate the change in state, or the indicator 12 may also include anauditory signaler 14 to indicate the change in state. Other indicators12, or combinations of indicators 12, are also possible.

Embodiments of the patch 1 can be placed anywhere on the scalp asplacing a conventional wired EEG electrode. The patch 1 self-adheres tothe scalp either through a conductive adhesive, an adhesive with aconductive, and/or through mechanical means such as intradermal fixationwith a memory-shape metal, or the like.

Once attached to the scalp, some embodiments enable the patch 1 toperform as a single-channel seizure detection device. In thisembodiment, the patch 1 records a single channel of differential EEGcontinuously, uninterrupted for up to seven days. Following a recordingsession, the patch 1 may be placed in the mail and returned to a servicethat reads the EEG to identify epileptiform activity according to ACNSguidelines. In other embodiments, data may be retrieved from the patch 1via I/O data retrieval port 10 and uploaded or otherwise sent to aservice for reading the EEG data. I/O data retrieval port 10 may operatewith any suitable I/O protocol, such as USB protocol, Bluetoothprotocol, or the like. Epileptiform activity such as seizures andinterictal spikes may be identified in a report along with EEG recordingattributes and made available to physicians through a user's electronicmedical records, or the like.

In another embodiment, the self-contained patch 1 may also employcapacitive coupling, such as is disclosed in U.S. Pat. App. Pub.2010/0222686, as a means to “spot-check” signal quality. In thisembodiment, a handheld, or other device, is brought near the patch 1 tocapacitively couple with the device as a means to interrogate the EEG orimpedance signal in real time.

In another embodiment, the self-contained patch 1 may be used to alertto seizures in real time, or near real time. In this embodiment thepatch 1 may continuously transmit to a base station 21 that runs seizuredetection algorithm(s) in real-time. The base station 21 may sound analarm if a seizure is detected either at the base station 21 itself, orthrough communication to other devices 22 capable of providing a visualand/or audio and/or tactile alarm. The base station 21 may also keep arecord of EEG for later review by an epileptologist. These EEG may alsobe archived in electronic medical records, or otherwise stored.

In another embodiment, the self-contained patch 1 could be used torecord ultra-low frequency events from the scalp such as corticalspreading depressions. In this embodiment, the amplifier circuitry 7 maybe appropriate for recording DC signals. Alternatively, the amplifiercircuitry 7 may be appropriate for recording both DC and AC signals. Thepatch 1 in this embodiment may be used after a suspected stroke event asa means to monitor for the presence or absence of cortical spreadingdepressions and/or seizures or other epileptiform activity. The patch 1in this embodiment may be placed on the scalp of a patient by any typeof health care provider such as an emergency medical technician, medicaldoctor, nurse, or the like.

In yet another embodiment, the patch 1 may employ capacitive coupling,such as that disclosed in U.S. Pat. App. Pub. 2010/0222686, to monitorfor cortical spreading depressions in real time. In this embodiment, thespreading depressions could be analyzed over time and displayed as avisualization of the EEG. The patch 1 may store these EEG (e.g., instorage 9) for later retrieval. These EEG could also be archived inelectronic medical records, or the like.

In another embodiment shown, for example, in FIGS. 2 & 4, theself-contained patch 1 has three electrodes 4, 5, 6 and is used as atool to record frontal EEG below the hairline before, during, and aftersleeping. The electrode 4, 5, 6, spacing is based on typical devicesused to record the stages of sleep from frontal EEG. As with thesetypical devices, the patch 1 in this embodiment is meant to be placedbelow the hairline, centered with the nose where the electrodes make aparallel line with the eyes. Electrodes 4 and 6 are referenced toelectrode 5.

In this embodiment, the patch 1 has the ability to be turned on and offvia recording state switch 15 when needed either through a magneticfield-effect element 17 or through a switch 16 such as a membrane-type,or momentary-type switch, built into the enclosure 2 of the patch 1. Forembodiments of the patch 1 using a recording state switch 15 comprisinga magnetic field-effect switch 17, such as a Hall-effect sensor, thepatch 1 may simply be placed in a receiver cradle, or the like, thatcontains a magnetic element that changes the recording state of thepatch to a sleep state. Removing the patch 1 from the cradle, andsubsequent removal of the magnetic field, could then cause the magneticfield effect switch 17 to change the patch 1 from a sleep state to arecording state. Likewise, in this embodiment, the self-contained patch1 may also include a recording state indicator 12 to indicate the changein recording state from record to sleep, or from sleep to record. Thisindicator may be an LED element 13 that flashes to indicate the changein state. This indicator may also be, or include, an auditory indicator14 to indicate the change in state. Other indicators, or combinations ofindicators, are also possible.

In this embodiment, after the patch 1 is in record mode, the patch 1 isthen placed on the scalp below the hairline using a conductive hydrogel18, or the like, that also provides enough adhesion to the scalp foreffective recording of EEG for up to a twelve hour period.Alternatively, the patch 1 may be adhered with a combination conductivehydrogel 18 with an adhesive construct. The EEG data itself is recordedin the standard European Data Format (EDF), or any other suitableformat. After nightly use, the conductive hydrogels 18 can simply bepeeled off of the patch and thrown away. Prior to the next night's use,new conductive hydrogels 18 can be applied to the patch as applying asticker. FIG. 4 is a perspective bottom view illustration of replaceableconductive hydrogels 18 that interface between the self-contained EEGrecording patch 1 and the scalp on an embodiment of a three-electrodeEEG device 1. FIG. 5 is a perspective bottom view of an illustration ofreplaceable conductive hydrogels 18 that interface between theself-contained EEG recording patch 1 and the scalp on an embodiment of atwo-electrode device. Other configurations and hydrogels 18 are alsopossible.

This process of recording EEG each night may be done for up to tennights with a single patch 1. In this embodiment, the patch 1 may beused to record the different stages of sleep for multiple nights in manydifferent environments such as in the user's home. Once ten nights ofEEG have been recorded, the patch 1 may be placed in the mail to aservice that reads the EEG to identify sleep stages according to AASMguidelines. In other embodiments, the data on the patch 1 may beaccessed via I/O data retrieval port 10 and uploaded, or otherwise sentto a service. Sleep architecture may be identified in a report alongwith EEG recording attributes and made available to physicians through auser's electronic medical records, or the like. Alternatively, the rawEDF data can be made available to physicians for review.

FIG. 6 is an exemplary state diagram for an embodiment of theself-contained EEG recording patch in accordance with the disclosure. Asshown in FIG. 6, embodiments of the self-contained EEG recording patch 1may have a dormant state 60 in which the patch 1 is awaiting activationin a deep sleep and lowest current mode. Upon a full boot andinitialization, the patch 1 may enter an unconfigured state 62 wherepatch 1 is awaiting configuration with analog supply off and in a lowcurrent mode. Upon connection of a USB to a host, patch 1 may enter aUSB connected state 64. Upon a configuration file being written, patch 1may enter a USB configured state 66. While patch 1 remains USBconfigured (e.g., magnet attached, or device cradled, switched off, orthe like) it may be in a deep sleep ready mode. Upon activation (e.g.,magnet removed, or device removed from cradle, or switched on, or thelike) the patch 1 may enter a recording state 68. As also indicated,patch 1 may enter an exceptional state 69 when a power source ismissing, depleted, or the like.

FIG. 7 is an exemplary state diagram for another embodiment of theself-contained EEG recording patch in accordance with the disclosure. Asshown, embodiments of the self-contained EEG recording patch 1 may havea dormant state 70 where the device is hibernating. Upon activation(e.g., magnet removed, or device removed from cradle, or switched on, orthe like) the patch 1 may enter a recording state 71. From recordingstate 71 the patch 1 may also enter an impedance check state 72 fromwhich patch 1 may return to recording state 71 upon completion of theimpedance check. Patch 1 may enter another power source dead state 73 ifa power source dead or storage 9 is full condition is detected. Thepatch may also enter a USB commissioned state 74 when a USB connectcondition is detected. Initially, a patch 1 may be in an uncommissionedstate 75 until connected to a host via USB, or the like, when it entersa USB connected state 76. Other conditions for entering the variousstates are also indicated on FIGS. 6-7.

FIG. 8 is an electronic circuit layout illustration for an embodiment ofthe self-contained EEG recording patch in accordance with the disclosureshowing components and power source 11 (e.g., a battery, capacitor, orthe like) with the patch enclosure 2 removed. As also shown, eachelectrode 4, 5, 6 may have amplification circuitry 7 as disclosedherein.

FIG. 9 is an electronic circuit layout illustration for an embodiment ofthe self-contained EEG recording patch in accordance with the disclosureshowing components without the power source 11 (e.g., battery,capacitor, or the like) and without the patch enclosure 2. In someembodiments, as shown, storage 9 and data processor 8 may be located inthe space under power source 11.

FIG. 10 is an electronic circuit layout illustration for the top (leftside of FIG. 10) and bottom (right side of FIG. 10) sides of anembodiment of the self-contained EEG recording patch 1 showingcomponents in another layout in accordance with the disclosure withoutthe power source 11 (e.g., battery, capacitor, or the like) or over-moldenclosure 2 on the top. The electrodes 4, 5, programming pads, 10, andI/O programming pads 10 are visible on the bottom side of the patch 1.The top side of the patch may house the amplification circuitry 7, dataprocessor 8, and storage 9 as shown.

FIG. 11 is an exploded perspective view of an electronic circuit layoutillustration for an embodiment of the self-contained EEG recording patch1 in accordance with the disclosure showing the enclosure 2 overmolding,power source 11, transmitter 19 and circuit board substrate 20. Otherconfigurations are also possible.

FIG. 12 is a schematic illustrating an embodiment of the self-containedEEG recording patch 1 as a seizure alerting method in accordance withthe disclosure whereby the transmitter 19 in the patch 1 attached to thescalp transmits EEG in real-time to a base station 21 that analyzes theEEG for seizures and stores the EEG for later retrieval. Once a seizureis detected the base station 21 can alert to the seizure and/or relaythe alert to other devices 22 such as a smart phone, alarm, or the like.

FIG. 13 is a schematic illustration demonstrating the concept ofsingle-channel seizure detection based on scalp location in accordancewith the disclosure. In this schematized example, an embodiment of thepatch 1 fits between any two electrodes (e.g., F7-F8, Fp1-Fp2, T3-T6,O1-O2, F3-F4, P3-P4, C3-C4, Fz, Cz, and Pz) in the typical wired EEG.For example, a seizure is recorded by the F7-T3 and F3-C3 wiredelectrode pairs. Likewise EEG Patch 1 a, located between these wiredpairs, will also record spike-wave discharges, whereas wired pair Fz-Czand EEG Patches 1 b-1 d, do not record seizure activity demonstratingthe potential for scalp-specific locations for seizure detection.

FIG. 14 is a schematic illustration of a map of the scalp showing anexample of single channel seizure detection performance as a probabilitymap for an individual person based on standard EEG electrode locationsin accordance with the disclosure. In this example there is a ‘bestchannel’ 30 that has the highest probability for detecting futureseizures in this particular person. These maps may be generated for eachperson's seizure signature to identify the best scalp location to placethe patch 1 to reliably detect seizure activity.

FIG. 15 is an exploded perspective view of the electronic circuit layoutillustration for the bottom of an embodiment of the self-contained EEGrecording patch 1 in accordance with the disclosure showing components,I/O programming and retrieval 10, dais boards 80 off of the substrate20, containing electrodes 4, 5, and power source 11, with the patchenclosure 2 removed. Other configurations are also possible.

FIG. 16 is an electronic circuit layout illustration for the bottom ofan embodiment of the self-contained EEG recording patch 1 in accordancewith the disclosure showing components, I/O programming and dataretrieval 10, dais boards 80 surface-mounted to the substrate 20, withelectrodes 4, 5, and power source 11 with the patch enclosure 2 removed.Other configurations are also possible.

Another embodiment of the “dais assembly” construction described aboveuses standard immersion silver as the electrode 4, 5, 6 surface finish.The dais boards 80 are then masked to expose only the electrode 4, 5, 6,metal surface using known printed circuit board lithography techniques,and placed in a bath containing sodium hypochlorite solution to developa silver chloride layer on the surface of the silver electrode 4, 5, 6.This method leverages known printed circuit board fabrication techniquesand equipment to fabricate an Ag—AgCl biopotential electrode. Thefinished dais boards 80 are then attached to the main circuit board orsubstrate 20 as described above.

In another embodiment shown, for example, in FIGS. 17, 18, 19 & 20, theself-contained EEG recording patch 1 has two memory shape alloyelectrodes 90 that are used to mechanically fix the patch 1 to apatient's scalp. Plungers 91, are used to inject the memory shape alloyelectrodes 90 into the scalp. The memory shape alloy electrodes 90,facilitate low-impedance connections between the patch 1 and the scalpfor recording biopotentials.

FIG. 17 is a sectioned view of the electronic circuit layoutillustration for the bottom of an embodiment of the self-contained EEGrecording patch 1 in accordance with the disclosure showing components,memory shape alloy electrodes 90 in their storage state, the plungers91, used to inject the memory shape alloy electrodes into the scalp formechanical fixation to the scalp, and power source 11 with the patchenclosure 2. Other configurations are also possible.

FIG. 18 is a top perspective view of an embodiment of the self-containedEEG recording patch 1 in accordance with the disclosure showing theplungers 91 with the patch enclosure 2. Other configurations are alsopossible.

FIG. 19 is a side view of an embodiment of the self-contained EEGrecording patch 1 in accordance with the disclosure in accordance withthe disclosure showing memory shape alloy electrodes 90 in theirdeployed state, but not yet retaining their memory shape, and theplungers 91 used to inject the memory shape alloy electrodes into thescalp with the patch enclosure 2. Other configurations are alsopossible.

FIG. 20 is a sectioned view of the memory shape alloy 90 mechanism inits storage state with plunger 91. Other configurations are alsopossible.

Although various embodiments have been shown and described, the presentdisclosure is not so limited and will be understood to include all suchmodifications and variations are would be apparent to one skilled in theart.

What is claimed is:
 1. A self-contained electroencephalogram (EEG)recording patch adapted to be worn by a user, comprising: a patchhousing that encloses: a substrate having a power source; a single pairof measuring electrodes; a memory; and circuitry disposed thereon; anI/O port that provides a physical interface for communication betweenthe memory and an external device; the patch housing including a surfacehaving apertures for the single pair of measuring electrodes and the I/Oport; and a sticker including hydrogel adapted to reversibly attach tothe surface of the patch housing and reversibly attach the patch to ascalp of the user; wherein: in an attached condition, the stickercompletely covers the I/O port; and in a detached condition, the stickeris removed from the surface of the patch housing; the circuitry, afteractivation of the patch, is configured to use the power source to enterthe patch into a disconnected, continuous recording state for recording,using the single pair of measuring electrodes, EEG data into the memoryfor a time period lasting at least 12 hours, wherein: in thedisconnected, continuous recording state, the patch is in the attachedcondition and the EEG data is not transmitted to the external device;and in a connected, non-recording state, the patch is in the detachedcondition and the circuitry is configured to communicate the EEG data tothe external device using the I/O port.
 2. The patch of claim 1,comprising a plurality of replaceable stickers adapted to reversiblyattach to the surface.
 3. The patch of claim 1, wherein the patch doesnot include a wireless communication mechanism.
 4. The patch of claim 1,wherein the time period lasts up to 170 hours.
 5. The patch of claim 1,wherein the circuitry performs an impedance check, using the single pairof measuring electrodes, prior to entering into the disconnected,continuous recording state.